Method of making a stud fastener assembly with integral lock

ABSTRACT

A method of making a stud fastener assembly having both ends thereof threaded and a lock ring in slidable but captive engagement between the said threaded ends so that said lock ring is not disengageable therefrom whereby the lock ring is slipped onto the stud fastener subsequent to threading one end thereof and thereafter threading the opposite end of said fastener.

United States Patent [1 1 Rosan, Sr. et al.

1 METHOD OF MAKING A STUD F ASTENER ASSEMBLY WITH INTEGRAL LOCK [75] Inventors: Jose Rosan, Sr., San Juan Capistrano; Jose Rosan, Jr., Newport Beach, both of Calif.

[73] Assignee: Rosan Engineering Corp., Newport Beach, Calif. by said Rosan [22] Filed: Sept. 23, 1971 [21] App1.No.: 182,944

Related US. Application Data [62] Division of Ser. No. 32,081, April 27, 1970, Pat. No.

[52] US. Cl ..10/27 R, 29/437, 29/509, 29/522 [51] Int. Cl. ..B21k 1/44 [58] Field of Search ..29/509, 522, 437; 10/10 R, 10/27 R; 151/4173 1March 20, 1973 [56] References Cited UNITED STATES PATENTS 1,440,802 1/1923 Smith ..10/27 R 2,270,813 1/1942 Olson ..10/10 R 2,788,830 4/1957 Rosan ....151/41.73 X 3,163,872 l/1965 Rosan et al. ..10/1ORX 3,259,161 7/1966 Rosan ....151/41.73 3,346,935 10/1967 Lyon ..29/522 X 3,571,904 3/1971 Gulistan ..l0/l0 R X Primary Examiner-Charlie T. Moon Attorney-Roman A. Di Meo 5 7 ABSTRACT A method of making a stud fastener assembly having both ends thereof threaded and a lock ring in slidable but captive engagement between the said threaded ends so that said lock ring is not disengageable therefrom whereby the lock ring is slipped onto the stud fastener subsequent to threading one end thereof and thereafter threading the opposite end of said fastener.

5 Claims, 6 Drawing Figures METHOD OF MAKING A STUD FASTENER ASSEMBLY WITII INTEGRAL LOCK This is a division of application Ser. No. 32,081 filed Apr. 27, 1970, now US. Pat. No. 3,620,252.

With the advent of more sophisticated motors, engines and the like having speeds of high revolution and the attendant vibration problems resulting therefrom, it has become increasingly necessary to obtain extraneously installed studs capable of being locked into place without the possibility of being loosened due to the aforesaid high vibrational forces. This problem has been solved by using a lock ring in conjunction with the stud to form a stud fastener assembly, said lock ring being externally and internally serrated whereby the internal serrations thereof engage cooperating serrations on the stud body and the lock ring. After the lock ring is displaced into integral engagement with the workpiece, since its external serrations engage the workpiece material, rotation of the lock ring, and a fortiori the stud, is prohibited, and concomitantly helical displacement ofthe fastener is also prohibited.

However, an inventory and installation problem could conceivably occur by the use ofa separate nonintegral lock ring in conjunction with the stud fastener. The instant invention anticipates and avoids this problem by providing a method of making a stud fastener which maintains the lock ring in permanent limited slidable engagement with the threaded ends of the stud fastener. This is achieved as will hereinafter be more fully described by threading one end of a stud blank, placing the lock ring onto the stud blank over the nonthreaded opposite end, and thereafter threading the nonthreaded end of the stud blank. Thus while the lock ring is in slidable engagement with the stud body its longitudinal movement is limited in either direction by the threads on the stud body formed on opposite sides of the lock ring. Therefore, when the stud is threaded into a workpiece bore the depth of its installation will be limited by the slidable lock ring contacting the bottom thread convolution of the threads of the external portion of the stud, thereby providing a positive means for installing the studs of the instant invention to a uniform depth.

Accordingly, the principal object of this invention is to provide a method for making a stud fastener assembly which can be permanently locked into a workpiece by means of a serrated lock ring wherein the lock ring is in captive relationship with the stud body.

Another object is to provide a method for making a stud fastener assembly which can be permanently locked into a workpiece by means of a serrated lock ring wherein the lock ring is captive, but in movable relationship with the stud fastener body.

Still another object is to provide a method for making a stud fastener assembly which can be permanently locked in a workpiece by means of a serrated lock ring wherein the stud fastener is further provided with means for positively installing the same at a uniform depth.

Other objects and advantages will be readily apparent from the description taken in conjunction with the accompanying drawings in which;

FIG. 1 is an elevational, partly sectioned, view of the stud fastener assembly of the instant invention threaded into a workpiece, but prior to displacing the serrated lock ring into locking position into the workpiece material;

FIG. 2 is an elevational, partly sectioned, view of the stud fastener assembly shown in FIG. 1, illustrating the lock ring displaced into the workpiece material in locking position;

FIG. 3 is an elevational view of the stud body of the stud fastener assembly of FIG. 1;

FIG. 4 is a cross sectional view of the stud body shown in FIG. 3 taken on the line 44 thereof;

FIG. 5 is a top plan view of the lock ring shown in FIG. I; and

FIG. 6 is an elevational, partly sectioned view of the lock ring shown in FIG. 5.

Referring more particularly to FIGS. 14, reference numeral 10 designates generally the stud fastener assembly of the invention having a bodyj ll provided with external threads 12 and 13. Stud body 11 is shown threaded into workpiece bore 15 of workpiece 16 and in threaded engagement with internal threads 17 of bore 15 of the workpiece. Body 11 is further provided with longitudinally extending flutes or serrations 14 interposed between the innermost thread convolutions 12a and 13a (as best seen in FIG. .3) of external threads 12 and 13, respectively. External threads 12 and 13 may be similar or different in size from each other, but in any event the minimum crest diameters of both of said thread convolutions must exceed the maximum crest diameter of the internal serrations of the lock ring for reasons which will hereinafter be more particularly described.

Although not shown, an annular groove may be positioned between the uppermost end of longitudinal serrations 14 and the innermost thread convolution 12a so as to result in an area of reduced cross section, thereby providing preselected or preferential breaking or shearing points in the event of excessive torsional or shearing force applied to the stud body. This avoids a recurring problem whereby under such forces the stud body normally fractures approximately one to two thread convolutions below the point of contact of the fastener threads with the workpiece bore threads.

Lock ring 18 is provided with external serrations l9 and internal serrations 20 (as best shown in FIGS. 5 and 6). Internal serrations 20 of lock ring 18 are in slidable engagement with longitudinal serrations 14 of body 11. As hereinabove mentioned, regardless of the size of external threads 12 and 13 of body 11, the crest diameters of both threads exceed the crest diameter of the internal serrations 20 so that although lock ring 18 is afforded axial movement relative to the body 1 1, said movement is limited by the engagement of the upper portion of internal serrations 20 with lead thread convolution 12a and the engagement of the lower portion of internal serrations 20 with lead thread convolution 13a. It is thus evident that lock ring 18 is made an integral, captive member of the stud. fastener assembly.

As stud body 11 is threaded into bore 15 of workpiece 16, no interference results from the captive nature of lock ring 18 since the lock ring will ride axially along serrations 14 of body 11. Further, when the upper portion of internal serrations 20 abuts against thread convolution 12a, further threading of body 11 into the bore of the workpiece is: resisted, thereby indicating that the stud is installed to the prescribed depth. Therefore, prior to displacing the lock ring 18 into its locking position it serves the function of providing a positive stop means thereby obtaining uniform installation of the stud fastener.

After the stud fastener is threaded to its predetermined depth, an axial force is applied to the uppermost portion of the lock ring 18, thereby embedding external serrations 19 thereof into the workpiece material adjacent counterbore 15a of bore 15. It is obvious that the workpiece material located between the crests of the external serrations 19 of lock ring 18 provides a resistant force to subsequent rotational movement of the lock ring. By virtue of the interengagement of internal serrations 20 of lock ring 18 and external serrations 14 of stud body 11, rotational movement of stud body 11 is also prohibited thereby eliminating the helical displacement of stud body 11 and maintaining the stud fastener in tight integral association with the workpiece.

The fastener of the instant invention is made by first externally threading a stud blank so as to provide the external threads 13. Either concurrent therewith, or immediately subsequent thereto, external longitudinally extending serrations 14 may be formed. External threads 13 may be formed by any conventional means such as thread rolling and the like, and external serrations 14 may also be formed by any conventional methods such as knurling, grinding, cutting and the like.

After the formation of external threads 13 and external serrations 14, lock ring 18, upon which is formed external longitudinally extending serrations l9 and internal serrations 20, is slipped over the blank end of the stud body so that internal serrations 20 interengage external serrations 14 of the body. It should be noted that external threads 13 of the body are formed so that the minimum crest diameter thereofis larger than the maximum crest diameter of the external serrations 20 of lock ring 18 thereby prohibiting longitudinal disengagement of the lock ring.

Thereafter, the unformed end opposite threaded portion 13 of body 11 is threaded to form external threads 12. External threads 12 are formed by a thread rolling process. Thus, although the unformed portion of body 11 over which lock ring 18 is slipped must of necessity initially have a lesser diameter than the crest diameter of internal serrations 20 of lock ring 18, by thread forming, the roots and crests rather than cutting the same, the material initially located thereat is caused to flow and be displaced outwardly so as to form the crest of the threads. Therefore, by use of this process, the crest diameter of the threads so formed will exceed the initial diameter of the blank shank from which it was formed. Thus, the crests of the external threads 12 are formed to have a diameter greater than the crest diameter of internal serrations 20 of the lock ring.

While one embodiment of the invention has been described, it is understood that the particular embodiment of the invention herein disclosed is for illustrative purposes only and that various changes may be made therein without departing from the principles of the invention.

We claim:

1. The method of forming a stud fastener assembly having an integral captive lock ring, comprising the steps of:

forming external threads on a portion of a cylindrical stud blank so that the diameter across the crests thereof is greater than the diameter of the stud a forming external longitudinally extending serrations about the outer periphery of said body blank between the first formed external threads and the opposite end of said blank; forming a lock ring with external and internal longitudinally extending serrations so that the maximum diameter of the crests of the internal serrations thereof is less than the minimum diameter across the crests of said threads; slipping said lock ring over the unformed end of said stud body blank and displacing said lock ring longitudinally relative to said body blank until at least the trail end of said internal serrations of the lock ring are interengaged with the external longitudinally extending serrations of the body; and

forming threads on at least a part of the unformed portion of the body blank so that the minimum diameter across the crests of said second formed threads is greater than the maximum diameter of said internal serrations of said lock ring.

2. The method of forming a stud fastener assembly as defined in claim 1, wherein the second formed threads are formed by thread rolling.

3. The method of forming a stud fastener assembly as defined in claim 2, wherein the second formed threads are formed so as to intersect the external longitudinally extending body serrations.

4. The method of forming a stud fastener assembly as defined in claim 3, wherein the internal longitudinally extending body serrations intersect the first formed threads of the body. 7

5. The method of forming a stud fastener assembly as defined in claim 4, wherein the first formed threads extend to one end of said body and the second formed threads extend to the other end of said body. 

1. The method of forming a stud fastener assembly having an integral captive lock ring, comprising the steps of: forming external threads on a portion of a cylindrical stud blank so that the diameter across the crests thereof is greater than the diameter of the stud blank; forming external longitudinally extending serrations about the outer periphery of said body blank between the first formed external threads and the opposite end of said blank; forming a lock ring with external and internal longitudinally extending serrations so that the maximum diameter of the crests of the internal serrations thereof is less than the minimum diameter across the crests of said threads; slipping said lock ring over the unformed end of said stud body blank and displacing said lock ring longitudinally relative to said body blank until at least the trail end of said internal serrations of the lock ring are interengaged with the external longitudinally extending serrations of the body; and forming threads on at least a part of the unformed portion of the body blank so that the minimum diameter across the crests of said second formed threads is greater than the maximum diameter of said internal serrations of said lock ring.
 2. The method of forming a stud fastener assembly as defined in claim 1, wherein the second formed threads are formed by thread rolling.
 3. The method of forming a stud fastener assembly as defined in claim 2, wherein the second formed threads are formed so as to intersect the external longitudinally extending body serrations.
 4. The method of forming a stud fastener assembly as defined in claim 3, wherein the internal longitudinally extending body serrations intersect the first formed threads of the body.
 5. The method of forming a stud fastener assembly as defined in claim 4, wherein the first formed threads extend to one end of said body and the second formed threads extend to the other end of said body. 